savory tart dough

from Charlotte (from here)

1 1/2 c flour
1 stick butter, cut into cubes, chilled
1/2 tsp salt
1 large egg
2-3 tbsp cold water

In the bowl of a food processor, blend the flour and salt. Add in the butter and pulse until the butter is well incorporated into the flour - mealy consistency. Beat the egg into 2 tbsp of water and add the the processor and pulse briefly. If a dough doesn't form add cold water by tbsp and pulse after each addition until a dough forms. As soon as it comes together, stop pulsing. Gather the dough and form a disk. Roll out into a tart shape using parchment paper. Drape over the tart pan, pressing down into the pan, and roll off the excess dough using the rolling pin. Dimple the bottom of the tart with your fingertips, then spread 1 tbsp of dijon mustard evenly over the bottom.

Now the pastry is ready to fill and bake. Baking instructions are based on the filling.